1. Field of the Invention
The present invention is generally in the field of electrical circuits and systems. More particularly, the invention relates to electrical circuits and systems utilized in conversion of parallel data into serial data.
2. Background Art
A serializer can be used to convert low-speed data on a parallel input bus into high-speed data on a serial output. The parallel input bus includes multiple channels, which are sequentially selected by the serializer so as to transfer the data from the parallel input bus to the serial output. Conventional serializers typically include various features, which result in a slow conversion speed, high power consumption, and/or large size. Furthermore, many conventional serializer designs are not scalable and require substantial redesign when the number of channels of the parallel input bus is varied.
Conventional serializers typically convert the low-speed data into the high-speed data in multiple stages. For example, the parallel input bus can have sixteen channels where the low-speed data is converted by one stage into mid-speed data on four channels, which is then converted into the high-speed data on the serial output. However, designing a serializer with multiple stages can be result in a larger, slower, and/or more complicated design. Furthermore, these designs are typically not scalable, consume high power, and/or can be undesirably large. Conventional serializers may also place synchronization or re-time flip-flops and multiplexers or other combinational logic in a data conversion path of the serializer, thereby reducing conversion speed and increasing the size of the serializer. Some serializers may require a phase shifter to generate a signal for controlling selection of the channels in the serializer. However, the phase shifter can be difficult to design and is typically not scalable. Also, some serializers may utilize current mode logic (CML) for the conversion. While CML may be fast, additional circuitry may be required to convert from a complementary metal oxide semiconductor (CMOS) signal to a CML signal, thereby increasing the size of the serializer. Furthermore, CML requires a constant bias current resulting in high power consumption.
Thus, there is a need in the art for a serializer that can have high conversion speed, low power consumption, and small size while being scalable to accommodate variation in the number of channels of the parallel input.